Inkjet printers typically use one or more print head assemblies that include an ink supply and means for directing fine droplets of ink through an interface on to a print medium. These print head assemblies can experience problems with respect to the desired application of the ink, including accumulation and drying out of the ink at the interface. The typical interface is an orifice plate having hundreds of orifices through which the ink flows. To solve or at least minimize the ink accumulation and drying problem, the print head assemblies may be housed, or docked, in a “cap” when the inkjet printer is not printing. The cap is intended to create a humid environment in which the interface is kept free of dried-out ink. Cap design then becomes an important element in the overall design of an inkjet printer.